This invention relates to the field of walkers in general and, in particular, to rollable walkers for traversing stairs as well as substantially level surfaces.
Walkers can be broadly broken down into two categories in which the first category of walkers includes walkers designed to provide assistance while traversing substantially level surfaces and the second category of walkers include walkers designed to provide assistance while traversing stairs as well as substantially level surfaces.
Walkers for traversing substantially level surfaces generally include a four-legged frame as disclosed in U.S. Pat. No. 4,987,912 to Taylor and U.S. Pat. No. 4,993,446 to Yarbrough, and suffer from the disadvantage that they have to be lifted during ambulation, thereby causing a high degree of fatigue of the user. To overcome the problem of having to lift walkers, rollable walkers have been developed which include the provision of at least one pair of ground engaging wheels, casters or gliders as disclosed in U.S. Pat. No. 4,941,496 to Berning, U.S. Pat. 4,953,851 to Sherlock, U.S. Pat. No. 4,907,794 to Rose and others. However, rollable walkers suffer from the disadvantage of being somewhat unstable.
Other improvements over these walkers include the provision of a seat, sling or similar sitting device as disclosed in U.S. Pat. No. 4,907,839 to Rose et al. and the provision of foldable frames for minimizing their storage space requirements and for facilitating their portability when they are not in use.
Walkers for traversing stairs as well as substantially level surfaces also generally include a four-legged frame as disclosed in U.S. Pat. Nos. 4,941,496 to Berning; 3,176,700 to Drury; 3,387,618 to Swann; 4,094,331 to Rozsa; 4,411,283 to Locarelli; and, 3,421,529 to Vestal. As far as traversing stairs, these walkers suffer from the disadvantage that they have to be adjusted to the stairs geometry (i.e., the width and height of each stair in a stairway). Furthermore, these walkers have a characteristic upright build-up (i.e., a narrow base geometry,) and therefore are less stable when leaned upon by a user ascending or descending stairs. Further disadvantages of known walkers for traversing stairs such as the one disclosed in U.S. Pat. No. 4,922,940 to Lewy, are that there is no provision to accommodate the different postures taken up by the user depending on whether he is climbing or descending stairs or traversing substantially level surfaces. In addition, these walkers are not rollable, therefore they suffer from the above described disadvantage that they have to be lifted during ambulation, thereby causing a high degree of fatigue of the user.
There is therefore a need for walkers for traversing stairs as well as substantially level surfaces which overcome the above disadvantages.